A semiconductor substrate is handled on its edge and backside numerous times during the manufacturing process, for example during metal deposition, chemical vapor deposition, or etching processes. Such handling can cause contaminants to adhere to the backside of the substrate and travel from chamber to chamber, substrate to substrate, FOUP to FOUP, or process tool to process tool along with the substrate. These contaminants can migrate to the front side of the substrate, resulting in yield loss. Alternatively, the contaminants can cause the substrate to not lay flat on a substrate support in a process tool. For example, in a lithography step, the contaminants can undesirably cause a substrate to lay unevenly atop a support stage in a lithography tool beyond a working depth of field of the stepper lens.
Typical solutions to this problem have been to remove the contaminants through an in-production-line cleaning tool using wet chemicals, backside scrubbing, attempts to limit particle formation, and/or frequent cleaning of process tools. However, these steps only mitigate the yield loss and are costly in terms of equipment and consumables. For example, use of wet chemicals requires wet chemistry handling and disposal, and possible undesired damage to the backside of the substrate.
As such, the inventors have provided improved methods and apparatus for cleaning particle contamination from a substrate.